Normally when a vehicle breaks down or has trouble on the road, the driver can place a conventional triangular light reflecting warning sign, a warning cone, or a smoke flare behind the troubled vehicle for alert warning. The conventional light reflecting triangular warning sign and the warning cone work fine during daytime or high visibility hours. However, when the weather is rainy or foggy, with low visibility other drivers may fail to observe the warning sign or the warning cone and crash into the troubled vehicle.
The conventional light reflecting triangular warning sign and the warning cone also have the following shortcomings. Most of the conventional light reflecting triangular warning signs and the warning cones are not easy to store because of their sizes. Although the size of the conventional light reflecting triangular warning sign and the warning cone seem too large to fit well in the trunk of the vehicle, when they are placed on the road, they become too small to catch the attention of other drivers. The earlier the other drivers can detect the bad road conditions ahead, the more reaction time the other drivers may have to avoid the accident.
Another major disadvantage of the conventional light reflecting triangular warning sign and the warning cone is that they do not provide self-flashing or self-illuminating functions. As mentioned above, during low visibility conditions, such as bad weather or nighttime, other drivers may not be able to clearly observe the warning signs that would lead to an accident.
Although the smoke flare is highly visible during daytime, the flare does not stand out as much during the nighttime. Furthermore, since the flare can not be reused, it is not econormical and practical. Each flare can only last for certain designated hours. If the driver does not prepare enough flares, the driver would be in trouble when all the flares are burned out.